1. Field of the Invention
The invention relates to a package structure for a photosensitive chip, and more specifically to a package structure for a photosensitive chip, which can be easily manufactured and possess high production yields.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional package structure for a photosensitive chip is manufactured according to the following steps. First, a substrate 10, on which traces 12 are formed to define a plurality of zones 17, is provided. Then, a plurality of photosensitive chips 13 are arranged on the plurality of zones 17. Next, a frame layer 14 formed with a plurality of slots 16 corresponding to the traces 12 is adhered onto the substrate 10 via an adhesive layer 15. At this time, the photosensitive chips 13 on the substrate 10 are exposed via the slots 16. Then, a plurality of wires 18 are provided to electrically connect the photosensitive chips 13 to the substrate 10. Next, the substrate 10 is cut into package bodies each includes the frame layer 14, as shown in FIG. 2. Then, as shown in FIG. 3, a single package body is placed within a jig 22, and a zone for receiving a transparent glass 20 is defined. Next, the transparent glass 20 covers the frame layer 14 to finish the package processes of the photosensitive chip 13.
There are some drawbacks in the conventional package structure for a photosensitive chip. Thus, the manufacturing processes are complicated, the yield of products is low, and the package cost is high. The drawbacks are described as follows.
1. Since the frame layer 14 has to be glued onto the substrate 10 by the glue layer and then cut into a plurality of package bodies, the gluing process has to be added and the frame layer 14 has to be treated as wasted material. Thus, the package cost is increased.
2. Since the surface of frame layer 14 to which the transparent glass 20 is glued is a flat surface, the transparent glass 20 cannot be positioned on the frame layer 14. Accordingly, the jig 22 has to be provided when the transparent glass is to be glued onto the frame layer 14 so as to define the zone for receiving the transparent glass 20. Thus, the package cost is also increased.
3. When the glue layer 24 is applied onto the frame layer 14 to glue the transparent glass 20, the amount of the applied glue layer 24 is not uniform. Thus, the glued transparent glass 20 may be uneven, and the yield of the products may be influenced.
4. The covering process of the transparent glass 20 is performed after both of the substrate 10 and the frame layer 14 are cut into package bodies. At this time, the wasted material (chip) may contaminate the photosensitive chips 13. Therefore, the yield of the photosensitive chips 13 may be influenced.
In view of these drawbacks, it is therefore an object of the invention to provide a package structure for a photosensitive chip capable of solving the drawbacks of the package structure for a photosensitive chip and making it more applicable.
It is therefore an object of the invention to provide a package structure for a photosensitive chip, which is capable of simplifying the package processes, saving the material and thus lowering the manufacturing cost.
Another object of the invention is to provide a package structure for a photosensitive chip capable of facilitating the covering process of the transparent glass so as to improve the production yield.
Still another object of the invention is to provide a package structure for a photosensitive chip capable of smoothly attaching the transparent glass onto the frame layer and improving the production yield.
To achieve the above-mentioned objects, the invention provides a package structure for a photosensitive chip. The package structure includes a substrate having an upper surface and a lower surface, and a frame layer having a first surface and a second surface. The frame layer is formed on the substrate by way of injection molding with the first surface contacting the upper surface. A cavity is formed between the substrate and the frame layer. The second surface is formed with a depression in which plural projections each having a suitable height are formed. The frame layer is formed directly on the substrate by way of injection molding. The package structure further includes a photosensitive chip arranged within the cavity, a plurality of wires for connecting the substrate to the photosensitive chip, and a transparent layer rested on the projections within the depression. Accordingly, the yield can be improved and the manufacturing processes can be facilitated.